The present invention relates to an electromagnetic-wave shielding and light transmitting plate and a panel laminated plate of gas discharge type using a plasma display panel (hereinafter, referred to as xe2x80x9cPDPxe2x80x9d) and, more particularly, to an electromagnetic-wave shielding and light transmitting plate suitable for a front filter of a PDP (plasma display panel), which has good electromagnetic-wave shielding capability and near infrared ray blocking capability. The present invention also relates to a panel laminated plate in which a PDP is integrated with an electromagnetic-wave shielding and light transmitting plate to impart electromagnetic-wave shielding capability to the panel laminated plate itself, thereby lightening its weight, reducing its thickness, reducing the number of parts, and thus improving the productivity and reducing the cost and, in addition, to impart near infrared ray blocking capability, thereby preventing the malfunction of a remote controller.
With the spread of electronic appliances including office apparatuses and communication instruments, electromagnetic wave emission from these appliances has come into a problem. That is, adverse effect of electromagnetic wave to the human body is feared and it is also a problem that the electromagnetic wave affects precision apparatus to cause malfunction. Therefore, plates having good electromagnetic-wave shielding efficiency and light transparency have developed as front filters for PDPs of the office automation apparatuses and come into commercial use. Such plates are also used as windows of a place where a precision apparatus is installed, such as a hospital or a laboratory in order to protect the precision apparatus from electromagnetic waves f a portable telephone.
A conventional electromagnetic-wave shielding and light transmitting plate typically comprises transparent base plates such as acrylic boards and a conductive mesh member like a wire netting and is formed by interposing the conductive mesh member between the transparent base plates and by assembling them.
The applicant of this application has proposed an electromagnetic-wave shielding and light transmitting plate, having improved characteristics and allowing easier handling as compared with the conventional one, in which a conductive mesh member is interposed between two transparent base plates and integrally bonded together by transparent adhesives (JPA 11-74683).
This electromagnetic-wave shielding and light transmitting plate has good electromagnetic shielding capability and has light transparency so that distinct pictures are displayed. Further, it has the conductive mesh member interposed between the transparent base plates, thereby preventing scattering of fragments of the transparent base panels when damaged.
On the other hand, a PDP utilizing a discharging phenomenon has the following advantages in comparison to a liquid crystal display (LCD) and a cathode ray tube (CRT). Therefore, recently it has been researched and developed for practical use, for example, televisions, office automatic apparatus such as personal computers and word processors, traffic apparatus, boards, and other kinds of display panels.
1. It utilizes discharge light so that it is spontaneous light.
2. As its discharge gap is 0.1-0.3 mm, it can be shaped in panel.
3. By using fluorescent substances, it can emit colors.
4. It eases to make wide screen.
The basic display mechanism of the PDP is displaying of letters and figures by selective discharge emitting of fluorescent substances in many discharge cells which are disposed distantly each other between two plate glasses, and for example, has a mechanism as shown in FIG. 4.
In FIG. 4, a numeral 21 designates a front glass, 22 designates a rear glass, 23 designates a bulkhead, 24 designates a display cell (discharge cell), 25 designates an auxiliary cell, 26 designates a cathode, 27 designates a display anode, 28 designates an auxiliary anode. A red fluorescent substance, a green fluorescent substance, or a blue fluorescent substance (not shown) is provided in a film form on internal walls of each display cell 24 and these fluorescent substances emit light by electrical discharges when a voltage is applied between electrodes.
From the front surface of the PDP, electromagnetic waves with frequency from several kHz to several GHz are generated due to applying voltage, electrical discharge, and light emission, and the electromagnetic waves have to be shielded.
Moreover, for improving its display contrast, reflection of external light at the front surface has to be prevented.
The PDP in which the separate transparent plate is disposed in front of the PDP has defects as follows:
1. Structure for disposing two panels is complicated.
2. As a transparent base plate made of glass or the like is required for each of the PDP and the electromagnetic-wave shielding transparent plate, the PDP and the electromagnetic-wave shielding transparent plate are made thicker and heavier in total.
3. The number of parts and labor are increased, thereby raising the cost.
To solve the aforementioned problems and to provide a display panel of a panel laminated plate in which a PDP is integrally bonded to an electromagnetic-wave shielding member to impart electromagnetic-wave shielding capability to the panel laminated plate itself, thereby lightening its weight, reducing its thickness, reducing the number of parts, and thus improving the productivity and reducing the cost and, further, to impart near infrared ray blocking capability in addition to the electromagnetic-wave shielding capability, the applicant of this application has previously proposed a display panel comprising a PDP body, an electromagneticwave shielding member bonded to a front surface of the PDP body by transparent adhesives, a transparent base plate bonded to a front surface of the electromagnetic-wave shielding member by transparent adhesives, which is characterized by further comprising a heat-ray blocking layer interposed between the transparent base plate and the PDP body (JPA 11-119666).
In the display panel of JPA 11-119666, the PDP, the electromagnetic-wave shielding member, the heat-ray blocking layer, and the transparent base plate are integrally bonded together by transparent adhesives, thereby lightening its weight, reducing its thickness, reducing the number of parts, and thus improving the productivity and reducing the cost. In addition, the heat-ray blocking layer is also integrally laminated on the electromagnetic-wave shielding member, thereby obtaining excellent near infrared ray blocking efficiency.
In the electromagnetic-wave shielding and light transmitting plate and the panel laminated plate, the near infrared ray blocking capability is a very-important required characteristic for the purpose of securely preventing the malfunction of a remote controller. In particular, since the producing rate of near infrared ray is increased with the improvement of brightness of PDP, further improved near infrared ray blocking capability is desired.
When an acrylic board is employed as the transparent base plate, the near infrared ray blocking capability can be imparted to the base plate just by mixing material of copper series into acrylic resin as the raw material of the base plate. However, the acrylic resin has a problem on the heat resistance, that is, the acrylic resin is poor at heat and thus may be deformed by heat. Accordingly, the acrylic resin is not preferable as the raw material of the transparent base plate of the electromagnetic-wave shielding and light transmitting plate or the panel laminated plate. Therefore, it is desired to achieve an electromagnetic-wave shielding and light transmitting plate and/or a panel laminated plate having good near infrared ray blocking capability by using glass plate having excellent heat resistance as the transparent base plate. Further, also in case of using an acrylic board, it is also desired to have improved near infrared ray blocking capability.
It is an object of the present invention to solve the aforementioned problems and to provide an electromagnetic-wave shielding and light transmitting plate suitably used as an electromagnetic-wave shielding filter of a PDP which has good electromagnetic-wave shielding capability and good near infrared ray blocking capability, and having light transmitting capability so that distinct pictures are displayed.
It is another object of the present invention to provide a panel laminated plate in which a PDP is integrally bonded to an electromagnetic-wave shielding member to impart electromagnetic-wave shielding capability to the panel laminated plate itself, thereby lightening its weight, reducing its thickness, reducing the number of parts, and thus improving the productivity and reducing the cost and, further, to impart near infrared ray blocking capability in addition to the electromagnetic-wave shielding capability, thereby preventing the malfunction of a remote controller.
An electromagnetic-wave shielding and light transmitting plate of the present invention comprises at least one transparent base plate, an electromagnetic-wave shielding member, and a near-infrared ray blocking layer which are laminated and integrally bonded together, wherein said near infrared ray blocking layer is a combination of two near infrared ray blocking layers.
A panel laminated plate of the present invention comprises a plasma display panel body, an electromagnetic-wave shielding member, and a near infrared ray blocking layer which are laminated and integrally bonded together, wherein said near infrared ray blocking layer is a combination of two or more of near infrared ray blocking layers.
The electromagnetic-wave shielding and light transmitting plate of the present invention can obtain good electromagnetic-wave shielding capability and near infrared ray blocking capability because of the existence of the electromagnetic-wave shielding member and the near infrared ray blocking layer. In addition, since the near infrared ray blocking layer is composed of two or more of near infrared ray blocking layers and preferably of two or more of layer of different near infrared ray blocking materials, significantly improved near infrared ray blocking capability can be obtained by synergistic effect of the two or more of near infrared ray blocking layer.
In the electromagnetic-wave shielding and light transmitting plate of the present invention, concretely, two transparent base plates are integrally bonded to each other by transparent adhesives and said electromagnetic-wave shielding member and said near infrared ray blocking layer may be laminated between the transparent base plates or on an outer surface of the integrally bonded base plates.
The panel laminated plate of the present invention has the electromagnetic-wave shielding member and the near infrared ray blocking layer, thereby lightening its weight, reducing its thickness, reducing the number of parts, and thus improving the productivity and reducing the cost and, further the panel laminated plate can obtain good electromagnetic-wave shielding capability and near infrared ray blocking capability. In addition, since the near infrared ray blocking layer is composed of two or more of near infrared ray blocking layers and preferably of two or more of layers of different near infrared ray blocking materials, significantly improved near infrared ray blocking capability can be obtained by synergistic effect of the two or more of near infrared ray blocking layers.
In the panel laminated plate of the present invention, concretely, a transparent base plate is integrally bonded to the front surface of the plasma display panel body by transparent adhesives, said electromagnetic-wave shielding-member and said near infrared ray blocking layer are laminated between said plasma display panel body and the transparent base plate or on an outer surface of an integrally bonded unit.
In the present invention, the near infrared ray blocking layer may have the following structure:
(1) a combination of a first near infrared ray blocking film, composed of a base film on which a coating layer made of a first near infrared ray blocking material is disposed, and a second near infrared ray blocking film, composed of a base film on which a coating layer made of a second near infrared ray blocking material different from the first near infrared ray blocking material is disposed;
(2) a near infrared ray blocking film having a base film, a coating layer of a first near infrared ray blocking material disposed on one surface of the base film, and a coating layer of a second near infrared ray blocking material different from the first near infrared ray blocking material disposed on the other surface of the base film; or
(3) a near infrared ray blocking film having a base film, a coating layer of a first near infrared ray blocking material, and a coating layer of a second near infrared ray blocking material different from the first near infrared ray blocking material,:in which the coating layers are laminated to each other and to a surface of the base film.
In the present invention, a conductive mesh member made of metallic fibers and/or metal-clad organic fibers is preferably used as the electromagnetic-wave shielding member and when such a conductive mesh member is used, the safety is improved because the conductive mesh member prevents scattering of fragments when damaged.
When normal adhesives are used for the integration, there is a safety problem that fragments of the electromagnetic-wave shielding and light transmitting plate or the panel laminated plate are scattered when receiving an impact. However, since transparent elastic adhesives are used as the transparent adhesives, the scattering of fragments when damaged can be prevented, thereby improving the safety.